Move tracing namespace from base::debug to base::trace_event.

cc/scheduler/delay_based_time_source.h

Index: cc/scheduler/delay_based_time_source.h
diff --git a/cc/scheduler/delay_based_time_source.h b/cc/scheduler/delay_based_time_source.h
index ea03f9d9742ed2297cba0008e589d10fc3107a68..aa7157099c6cf728f968e3ad730aeb85bc8d2d66 100644
--- a/cc/scheduler/delay_based_time_source.h
+++ b/cc/scheduler/delay_based_time_source.h
@@ -12,9 +12,12 @@
 #include "cc/base/cc_export.h"
 
 namespace base {
-namespace debug {
+namespace trace_event {
 class TracedValue;
 }
+namespace debug {
+using ::base::trace_event::TracedValue;
+}

[Primiano Tucci (use gerrit), 2015/01/27 14:34:11]

nit: blankline

 class SingleThreadTaskRunner;
 }